Shutter shell encapsulating disk medium

ABSTRACT

A disk cartridge has two shell layers. The first layer encases the disk medium. The second layer encases the first layer. Both layers have a head access opening such that rotation of one layer relative to the other layer causes the head access openings to be aligned or misaligned. When the head access openings are misaligned the cartridge is closed. When the head access openings are aligned the cartridge is open.

BACKGROUND OF THE INVENTION

This invention relates to a cartridge based data storage system in whicha flexible magnetic disk is disposed within a cartridge shell. Moreparticularly, the invention relates to a double shelled cartridge forcontrolling access to the disk media.

Microprocessors and supporting computer technologies are rapidlyincreasing in speed and computing power while decreasing in cost andsize. These factors have led to the broad application of microprocessorsto an array of electronic products, such as hand-held computers, digitalcameras, cellular phones and the like. All of these devices have, ineffect, become computers with particular application-specificattributes. For this new breed of computer products, enormousflexibility is gained by the ability to exchange data files and storecomputer software.

A variety of proprietary storage devices have been used in computerproducts. For example, hand-held computers have used integrated circuitmemory cards ("memory cards") as the primary information storage media.Memory cards include memory storage elements, such as static randomaccess memory (SRAM), or programmable and erasable non-volatile memory,such as "flash" memory. Memory cards each are typically the size of aconventional credit card and are used in portable computers in place ofhard disk drives and floppy disk drives. Furthermore, memory cardsenhance the significant advantages of the size, weight, and batterylifetime attributes of the portable computer and increase portability ofthe storage media. However, because of the limited memory densityattainable in each memory card and the high cost of the specializedmemory chips, using memory cards in hand-held computers imposeslimitations not encountered in less portable computers, which typicallyuse more power-consuming and heavier hard and floppy disk drives astheir primary storage media.

Other of these computer products, such as the digital camera, haveemployed miniature video disks as the storage media. For example, U.S.Pat. No. 4,553,175 issued Nov. 12, 1985 to Baumeister discloses adigital camera configured to store information on a magnetic disk. InBaumeister, a signal processor receives signals representative of apicture from a photo sensor. Those signals are recorded on a magneticdisk for later processing. Unfortunately, the video disk storage productprovides limited storage capacity. For that and other reasons (e.g.,power consumption and cost), the video disk has not been used in othercomputer products. As a result, interchanging data from one of thesedigital cameras with other computer products, such as a hand-heldcomputer, is not readily achieved.

Miniature hard disk drives have also been suggested for use in portablecomputer products. For example, U.S. Pat. No. 5,469,314 issued Nov. 21,1995 to Morehouse et al. discloses a miniature hard drive for use inportable computer applications. In Morehouse, a hard disk drive isdescribed that is approximately 50 mm in diameter. While addressing manyof the problems presented by storage requirements in portable computers,the obvious problem of removability of the storage media is stillpresent.

Similar to a standard size cartridge, the miniature cartridge contains aflexible magnetic disk disposed within a hard outer shell. Such astandard size cartridge is disclosed in U.S. Pat. No. 4,445,157(Takahashi). The Takahashi patent is generally directed to a diskcassette that contains a flexible magnetic disk having a center core(i.e., a hub) and an apparatus for reading and recording information onthe flexible magnetic disk. The disk cassette comprises a flexible diskattached to a hub. The disk and hub assembly are sandwiched between anupper cover and a lower cover. The shutter slides over the outside ofthe cartridge to cover a head access opening.

A similar standard size cartridge is disclosed in U.S. Pat. No. Re,32,876 (Wakabayashi et al.). The Wakabayashi patent is also generallydirected to a disk cassette that contains a flexible magnetic diskhaving a center core (i.e., a hub) and for storing information. The diskcassette comprises a flexible disk attached to a hub. The disk and hubassembly are sandwiched between an upper cover and a lower cover. TheWakabayashi shutter rotates on the interior of the cartridge andcomprises a metal sheet that slides over a disk access opening to covera head access opening. This interior shutter works okay for disk thathave low revolution speed in which aero dynamics of the disk are not anissue. However, in a cartridge wherein the disk rotates at relativelyhigh velocities, the shutter could change the aerodynamics of the diskrotation and effect performance.

Thus, there is a need for an improved shutter mechanism.

SUMMARY OF THE INVENTION

In accordance with the present invention a mini-cartridge is providedfor mini drives in a plurality of hand-held devices which generatesignals representing different functions performed by different classesof the devices. For example, the devices include digital cameras,electronic books, global positioning systems, personal digital systems,portable games and cellular phones. Each of these devices has a minidrive for writing signals and reading signals representing the functionsto and from a magnetic medium in the mini-cartridge. In this way,signals representing the diverse functions performed by the differentclasses of devices are recorded on the mini-cartridge. The hand-helddevices incorporating the present invention provide and create a singlemeans of capturing, moving and storing information across multipleproducts.

The present invention is directed to a data storage device thatcomprises a disk drive and removable cartridge. The cartridge for usewith the drive comprises an outer shell having a spindle access opening,a substantially circular magnetic medium rotatably disposed within theouter shell, and a hub connected to the magnetic medium proximate thecenter of the medium. The cartridge also comprises an inner shell havinga spindle access opening and a head access opening. The inner shell isrotatably coupled to the outer shell between first and second positions,and the spindle access openings of the inner and outer shells aresubstantially aligned. The inner shell is selectively rotatable to thefirst position so that the head access openings of the inner and outershells substantially align and the second position so that the headaccess openings are substantially misaligned. The circular medium isrotatably disposed within the inner shell.

The inner shell preferably comprises upper and lower inner shell halveshaving raised outer edges. The two shell halves are brought together sothat their edges overlap in frictional engagement to form a single innershell. The inner shell is substantially disc shape and has a hollowinterior wherein the disk media is rotatably disposed. The disk accessopening in the outer shell and the inner shell are substantially wedgeshaped. The inner shell comprises a sheet metal, preferably aluminum.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, there is shown in the drawings an embodiment that ispresently preferred, it being understood, however, that the invention isnot limited to the specific methods and instrumentalities disclosed. Inthe drawings:

FIG. 1 is a diagram of the interchangeable mini-cartridge of the presentinvention, including a plurality of devices each having a mini diskdrive, and including a caddy to adapt the mini-cartridge to a full-sizedrive of a host computer;

FIG. 2 is a top plan view of a disk drive according to the presentinvention;

FIG. 3 is an isometric view of a cartridge for use with the drive ofFIG. 1;

FIG. 4 is a top plan view of the cartridge of FIG. 2;

FIG. 5 is a bottom plan view of the cartridge of FIG. 2;

FIG. 6 is a side elevation view of the cartridge of FIG. 2;

FIG. 7 is an exploded view of the cartridge of FIG. 2;

FIG. 8 is a partially exploded view of the cartridge of FIG. 2 showingan internal shutter shell subsystem;

FIG. 9 is a top plan view of the cartridge of FIG. 2 with the uppershell half removed to reveal the operation of the shutter shell;

FIG. 10 is another top plan view of the cartridge of FIG. 2 with theupper shell half removed to reveal the operation of the shutter shell;

FIG. 11A-11E are illustration of the operation of shutter shell 16 inconjunction with the drive of FIG. 2;

FIG. 12 is a bottom isometric view of the cartridge of FIG. 2 showingthe lateral freedom of movement of the hub;

FIG. 13 is a cross section of the disk of FIG. 12 along the lines13--13;

FIGS. 14A-14D show cross sections of the cartridge and drive of FIGS.11A-11D along the lines 14--14 in various stages of insertion thecartridge into a disk drive;

FIG. 15A shows an isometric view of the load ramp of the presentinvention;

FIG. 15B shows the arms opened during media insertion to prevent damageto the media;

FIG. 15C shows the arms closed after media is fully inserted into thedrive;

FIG. 15D shows the heads loaded onto the load ramp and compressing abias spring;

FIG. 16 is an isometric view of the interior of a shutter shell andliner assembly showing the relative location of a media distortionneutralizer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The present invention provides a data storage cartridge for use with aremovable media type of disk drive. Throughout the description, apreferred embodiment of the invention is described in connection with aparticular sized and shaped disk cartridge. However, the disk cartridgedimensions and shape are presented for exemplary purposes only.Accordingly, the mechanism should not be limited to the particularcartridge embodiment shown as the invention contemplates the applicationto other cartridge and drive types and configurations.

FIG. 1 shows a plurality of devices 100a-100g, hereinafter collectivelydesignated as devices 100 which generate signals representing differentfunctions performed by different classes of the devices. For example,the global positioning system 100a can generate signals representingnavigational position. Electronic book 100b, digital camera 100c,personal digital assistant (PDA/ Palmtop) 100d, portable game 100e,cellular phone 100f, and laptop computer 100g each generate signalsrepresenting the function performed by that particular device. Each ofthese devices has a miniature disk drive 50 for writing the signals andreading the signals from a magnetic recording medium so that diversefunctions performed by different classes are recorded on the devices,i.e. a drive 50a for global positioning system 100a, a drive 50b forelectronic book 100 b, a drive 50c for digital camera 100c, a drive 50dfor PDA/palmtop 100d, a drive 50e for portable game 100e, a drive 50ffor cellular phone 100f, and a drive 50g for laptop computer 100g.

A mini-cartridge 10 has a magnetic recording medium on which the signalsfrom the devices are recorded. Mini-cartridge 10 is compatible with themini drives 50. Standard file formats maintain compatibility betweendevices 100. In the preferred embodiment, drives 50 are sized to fitwithin a PCMCIA form factor, preferably PCMCIA type II or type III, morepreferably type II. These form factors is commonly used in portablepersonal computers. For example, PCMCIA type II form factor is commonlyused for a modem connection of a notebook computer. PCMCIA type II formfactor is quite small so that miniature drive 50 readily fits into allof the portable, hand-held devices shown in FIG. 1. The miniature drive50 is insertable into and removable from the device just as the PCMCIAmodem is insertable into and removable from the PCMCIA slot of anotebook computer. Alternatively, the drive 50 could be hard wired,i.e., built-in, to the device. In both cases, the device generates adigital function signal which is connected to the magnetic heads of thedrive so that the digital function signal can be written on the magneticmedium of miniature cartridge 10. As an example, a digital functionsignal representing a picture taken in a digital camera 100c is recordedon a cartridge 10. This digital function signal can then be read byother classes of devices when the cartridge 10 is inserted into therespective other device.

FIG. 2 is a top view of a disk drive 50 with its top cover removed forclarity. Drive 50 accepts a removable disk cartridge 10 (shown inphantom) for reading and storing digital information. Drive 50 comprisesa chassis 57, an actuator 56 (preferably a rotary actuator), includingan opposing pair of load beams 44 having a read/write head 54 disposedat the end of each load beam, a load ramp 47, a spindle motor 53 and aspindle 40, and a shutter opening arm (not shown). The operation of diskmounting to spindle 40 is described more fully below. A disk cartridge10 can be inserted into the front of the drive in the directionindicated by the arrow. During insertion, cartridge 10 slides linearlyalong the top surface of chassis 57 and spindle motor 53 for engagementwith the read/write heads 54.

FIGS. 3-6 are isometric, top plan, bottom plan, and side elevation viewsof a miniature disk cartridge 10 that embodies aspects of the presentinvention. Miniature disk cartridge 10 has a number of differences froma full-size cartridges, such as the well-known 1.44 megabyte 3.5" floppydisk cartridge and the well-known ZIP disk cartridge) that prevent theminiature disk cartridge 10 from operating directly in a full-sizedrive. Perhaps, the most obvious of these differences is size. Diskcartridge 10 has a much smaller form factor than a full-size drivecartridge. Whereas a full size drive cartridge is about 4" square and1/4" high, a mini-cartridge less than about 2" wide square and about1/10" high. In particular, disk cartridge 10 has a width w preferably ina range of about 49 (1.9") to 51 mm (2"), most preferably about 50.1 mm,a length about 50 to 52.5 mm long, preferably about 51.8 mm, and athickness h less than about 2 mm (about 1/10") thick, most preferably1.95 mm. A large wedged shaped disk access opening 418 is disposed inthe front portion of disk cartridge 10 to provide selective access tothe media of cartridge 10. Disk cartridge 10 comprises a flexiblemagnetic disk 14 (partially shown in FIG. 5) and a disk media hub 12. Adriving access hole 218 provides an opening in cartridge 10 for drivespindle 40 (see FIG. 2) to engage hub 12 and drive flexible disk 14 pastopposing read write heads 54 (also shown in FIG. 2). Hub 12 is sizedslightly smaller than driving hole 218b, and as best shown in FIG. 4,hub 12 projects downwardly from cartridge 10. Cartridge 10 also has aside cut-out 34 and abutment surface 35. As explained more fully below,cut-out 34 and abutment surface 35 engage a sliding lever duringcartridge insertion and ejection. Cut-out 34 functions to retaincartridge 10 in drive 50 and ensure proper cartridge insertion whileabutment surface 35 provides a flat surface for engagement and springloading of sliding lever.

Referring also to FIG. 7, an exploded view of cartridge 10 is providedto more clearly show cartridge 10 interior components. Cartridge 10comprises top and bottom cartridge shell halves 18a and 18b,respectively, a rotary shutter shell having upper and lower halves 16aand 16b, respectively, upper and lower shutter shell liners 15a and 15b,respectively, a shutter pivot post 20, a shutter spring mechanism 22,and a shell stabilizer 24.

Cartridge 10 is about half the thickness of the well-known 3.5 inchfloppy disk. As a result convention removable cartridge shell materialscannot be used to construct cartridge 10. Plastics, such as those usedin the well-known 3.5 inch floppy disk, would either be too thick or notstrong enough if manufactured with the desired thickness. To manufacturea thin cartridge, such as cartridge 10, all of the component materialsmust be as thin as possible while providing structural support that willwithstand the rigors of everyday use. For example, cartridge shellhalves 18a and 18b are formed from a thin sheet material preferablyabout 0.1854 mm thick. To provide the structural support, the shell ispreferably made from a sheet metal. Preferably the metal is sheet steel,more preferably stainless steel, and most preferably series 300stainless steel. Cartridge shell halves 18a and 18b are preferably cutfrom a sheet of steel in a stamping operation which forms the turnededge portions 118a and 118b, provides the cutouts such as the drivinghole 218b in the bottom cartridge shell half 18b, post hole 218a in thetop cartridge shell half 18a, media access openings 418a, 418b, and soon.

Shutter shell halves also must meet strict thickness requirements. Assuch, shutter shell 16a and 16b are formed from a thin sheet material.The sheet material is preferably a sheet metal. The sheet metal ispreferably thin sheet aluminum, preferably 5052 aluminum, morepreferably in a half-hard condition. The sheet aluminum is preferablyabout 0.1854 mm thick. Shutter shell halves are also preferably cut froma sheet of aluminum in a stamping operation which forms upstanding rim116a in top shutter shell half 16a, upstanding rim 116b in the bottomshutter shell half 16b, and cuts driving hole 316b in the bottom ofshutter shell half 16b, pivot hole 316a in the top shutter shell half16a, and media access openings 416a, 416b in shutter shell halves 16aand 16b.

Upper shutter shell half 16a has a media distortion neutralizer 11disposed on the inner surface 216a of shutter shell half 16a. Distortionneutralizer 11 is located proximate the apex region of wedge shapedopening 416a. As described in further detail below, distortionneutralizer aids the planarity of media 14 as it approaches head loadramps during disk cartridge 10 insertion into drive 50. Distortionneutralizer provides a raised surface on upper shutter half 16a.Preferably the distortion neutralizer is formed directly on the surfaceof shutter half 16a, but could also be formed as a separate piece andattached by glue, welding, or the like.

Liners 15a and 15b are attached to shutter shell halves 16a and 16b.Liner 15a is attached to inside surface 216a of shutter shell half 16a;whereas liner 15b is attached to inside surface 216b of shutter shellhalf 16b. As described in detail below, disk media 14 rotates within theshutter shell and not the cartridge shell. Accordingly, unlike otherknown cartridges wherein the liners are typically attached to the insideof the cartridge shell, liners 15a, 15b are attached to the insidesurface of shutter shells 16a, 16b. Liners 15a and 15b are preferablyattached via an adhesive, more preferably a pressure sensitive adhesive.Liners 15a and 15b are cut to the shape of the surface to which theywill be attached (i.e., 216a, 216b ) from a sheet of liner material. Theliner material is preferably 100% polyester, more preferably Veratec141-620 available from Data Resources Group in Walpole Mass. The linermaterial has a thickness preferably in the range of about 3.35 mils toabout 3.8 mils, more preferably about 3.35 mils.

Stabilizer 24 is a substantially U-shaped spacer positioned in the rearportion of cartridge 10 and between upper and lower cartridge shellhalves 18a and 18b. Rear cartridge shell tabs 318a and 318b extendrearwardly from upper and lower shell halves 18a and 18b and wrap aroundstabilizer 24. Therefore, when cartridge 10 is assembled, a portion ofstabilizer 24 extends into and between the shell halves 18a and 18b andportions of stabilizer 24 protrude from joined upper and lower shellhalves 18a and 18b. The protruding portions of stabilizer 24 formportions of the outer contours of cartridge 10. In particular,stabilizer 24 forms cartridge rear comers 24a and 24b and forms rearportion 24c.

Stabilizer 24 is formed of a lightweight rigid material such as plastic.More preferably, stabilizer 24 is formed of high impact polystyrene. Itis formed from any one of the well-known plastic forming processes, suchas injection molding. Stabilizer 24 provides dimensional stability andrigidity to cartridge 10, thereby minimizing cartridge deformationduring mishandling, twisting, and so on.

Shutter spring mechanism 22 comprises a guide wire 23 and a roundhelical compression spring 21 that is slid over guide wire 23. Shutterspring mechanism 22 is fixed to stabilizer 24 at the ends of guide wire23. The ends seat in channels 124a and 124b that are formed into theends of U-shaped stabilizer 24. The operational details of shutterspring mechanism 24 are described in further detail below in connectionwith the description of cartridge opening and closing.

Flexible magnetic disk 14 is formed of a thin polymer film, such asMYLAR, and has a thin magnetic layer uniformly dispersed on the top andbottom surfaces thereof. The magnetic layer makes the flexible disk 14susceptible to magnetic flux and enables the storage of digital datawhen the disk surface is brought into magnetic communication with amagnetic transducer of the type commonly found in disk drives. Disk 14is generally circular with a circular hole proximate the center of disk14. Disk 14 has a radius in a range of about 20 to 25 mm, and preferablyabout 23.25 mm. Disk 14 has concentric tracks 114 that provide theformatting of disk 14 to store digital information. Disk 14 contains ahigh density of tracks per inch (TPI), preferably in a range of about2900 to about 3100 TPI, more preferably disk 14 contains about 3050 TPI.This high track density, which incidentally is much high that the common1.44 megabyte floppy TPI of about 10 TPI, allows the relatively smalldisk 14 to store at least 40 megabytes of digital data.

Media hub 12 is essentially donut shaped and comprises a ferrousmaterial such as steel, preferably stainless steel. The surface finishis about 8 micro inches to reduce sliding friction. Hub 12 comprises abore or hole 12a proximate the center, peripheral outer edge 12b andinner ring surface 12c. Inner ring 12c has an outer angled edge and asubstantially flat bottom surface. Outer peripheral edge 12b is alsoangled. Media hub 12 is firmly secured to disk 14 such that the centerof hub 12 is aligned proximate the center of disk 14. Media hub 12 ispreferably attached to disk 14 via a well-known adhesive process. Thedisk and hub assembly are rotatably disposed between upper and lowercartridge shutter shell halves 16a, 16b. Hub 12 is disposed in spindleaccess hole 316b of lower shutter shell 16b and spindle access hole 218bof lower cartridge shell 18b. As described in further detail below, theprotrusion of hub 12 from shutter shell 16 and an cartridge shell 18enhances coupling to a rotational power source, such as that provided bya drive spindle, when cartridge 10 is within drive 50 and acts arestraint on lateral movement of disk 14 when the cartridge is removeddrive 50.

As shown by FIGS. 7 and 8, shutter halves 16a and 16b snap together toform shutter shell 16, which houses media 14 and shutter liners 15a and15b (not shown in FIG. 5) which are attached to the inner surfaces ofshutter shells 16a and 16b respectively. The complete shutter assembly28 is pivotally attached to top shell 18. Hub 12 is attached to media 14and protrudes through drive access hole 316b in shutter shell 16b.Accordingly, when cartridge 10 is inserted and operating in drive 50,media 14 rotates within shutter shell 16. As best appreciated fromFigure unlike other disk cartridges which do not rotate within theshutter but which rotate within cartridge shell 18. Pivot post 20attaches shutter assembly 28 to upper shell half 18a by attaching thetop portion 20 to pivot hole 218b via shutter pivot hole 316. Pivot post20 is fixedly attached to top shell cartridge 18a while leaving anoffset space between and around post portion 20a and shutter pivot hole316a.

The use of an internal shutter shell provides several advantages overother internal shutter designs. Among the advantages are improvedcartridge 10 rigidity, improved disk 14 aerodynamics, and improvedshutter control. The improved rigidity results from cartridge 10 havingtwo layers of shell material (shutter 16 and shell 18) to guard againstmishandling. The improved disk 14 aerodynamics result from the fact thatspace within which disk 14 rotates is completely controlled and free ofdisturbances caused by other internal mechanical features. For example,in other internal shutter designs, the retracted shutter only covers aportion of the spinning disk thereby increasing the likelihood of airflow disturbances. The final example of the benefits of shutter 16 ofthe present invention is improved shutter opening control. Shutterstypically have a biasing mechanism to close the shutter. In the presentshutter design, a spring 21 provides such a bias. Here, spring 21 can belocated in the rear of the cartridge 10 and still control the operationof shutter 16.

When shutter assembly 28 is complete, media 14 is exposed at mediaaccess opening 416. However, and as described more fully below, media 14within cartridge 10 is only accessible from outside of cartridge 10 whenshutter access opening 416 aligns with cartridge shell access opening418. In such an alignment, shutter shell 16 moves to a first position sothat the openings 416, 418 completely overlap thereby "opening"cartridge 10. When the cartridge shell access opening 416 and cartridgeshell access opening 418 are misaligned, shutter shell 16 moves to asecond position such that the openings 416, 418 do not over lap thereby"closing" cartridge 10, shielding media 14 from ambient contaminants.

FIGS. 9 and 10 illustrate the "opening" and "closing" operation ofshutter shell 16 with spring mechanism 22. FIG. 6 is a top plan view ofcartridge 10 in the closed position with upper cartridge shell 18aremoved for clarity. FIG. 7 is a top plan view of cartridge 10 in theopen also with upper cartridge shell 18a removed for clarity. The motiveforce for biasing shutter 16 toward the closed position is provided bycompression spring 21 in an arcuate path. As noted above, compressionspring 21 is slid over arcuate guide wire 23, which is attached to theends of U-shaped stabilizer 24 in slots 124a and 124b. After attachmentof compression spring 21 onto guide wire 23, spring 21 follows thearcuate path established by guide wire 23. Other structures are possiblefor forming an arcuate spring path. For example, an arcuate channel cutinto the stabilizer 24 would also provide an arcuate path for spring 21.However, the use of guide wire 23 is preferred because it facilitatesconstruction of cartridge 10 by improving the handling of spring 21.That is, spring 21 easily conform to the shape of wire 23 which is thenattached to stabilizer 24.

Shutter shell 16 has an extending tab 17 that couples an translates aforce between shutter 16 and spring 21. Tab 17 is preferably formed intoshutter 16 but could alternately be attached to shutter shell 16 as aseparate part such as by welding. Tab 17 extends outwardly from shuttershell 16 so as to extend into the spring path, overlapping guide wire23. When cartridge 10 is in the closed position, compression spring 21engages tab 17 biasing shutter 16 toward the closed position. To opencartridge 10, a counterclockwise rotational force is applied to shuttershell 16 (from the perspective of FIGS. 6 and 7) against the bias ofspring 21, thereby compressing spring 21. When the rotational force isremoved from shutter shell 16, spring 21 biases shutter shell 16 back tothe closed position.

Cartridge 10 has several features (best described with respect to FIGS.9 and 10) that cooperate in the operation of shutter 16 in conjunctionwith drive 50. These features include, catch feature 516, flat noseportion 518, and retraction slot 618 (see FIG. 5 for an alternate viewof retraction slot 618).

Shutter catch feature 516 protrudes outwardly from the radius of shell16. Catch feature 516 provides two significant functions in theoperation of shutter 16: first, it provides a stop when spring 21 biasesshutter 16 toward the closed position; and second, it provides amechanism for coupling with drive 50 so that shutter 16 can be openedduring insertion into drive 50. The stop function of catch 16 operateswhen shutter 16 rotates toward the clockwise direction. When rotated tothe closed position, catch 516 engages the cartridge shell edge andthereby stops the rotation of shell 16.

Referring to FIG. 11A-11E, the operation of shutter shell 16 with drive50 is further illustrated. Referring to FIG. 11A, cartridge shell 18also has a flat nose portion 518 which is adjacent to catch feature 516when shutter shell 16 is in the closed position. Upper cartridge shell18a has an overhang 718, proximate flat nose portion 518, that shieldscatch 516 when the cartridge is not in drive 50. Shutter 16 is opened byshutter lever 48. Shutter lever 48 has a hook like portion 48a on itsproximal end. Hook like portion 48a has an upstanding tab portion 148that is adapted to engage shutter shell 16. When a cartridge 10 isinserted into drive 50, upstanding tab 148 engages flat nose portion518. The relatively flat and wide upstanding tab 148 and flat noseportion 518 provide sufficient area to ensure that lever 48 properly andreliably engages shutter 16. Additionally, flat nose portion 518enhances the pressure angle to more easily begin the rotation of shutter16. When properly engaged, an edge of upstanding tab 148 mates withcatch 516.

A retraction slot 618 is cut into the lower cartridge shell 18b.Retraction slot 618 permits the upstanding tab to retract, along withcatch 516, into cartridge shell 18 and move out of the way of the otherdrive 50 components. This ability to retract the shutter openingmechanism and catch 516 results in a larger disk access opening. FIG.11E illustrates cartridge 10 loaded fully into drive 50 with lever 48and shutter shell 16 fully retracted.

Shutter lever 48 is pivotally mounted at its distal end 48b to drivechassis 57 proximate the front portion of drive 50. Shutter lever 48 isbiased by a spring (not shown) in a clockwise direction (as viewed inFIGS. 11B-11E). As a result of the bias, lever 48 pivots to a positionedproximately as shown in FIG. 11B when a cartridge 10 is absent fromdrive 11.

As best illustrated in FIG. 11C, when cartridge 10 is inserted intodrive 50, the nose 518 of cartridge 10 engages shutter lever 48. At thepoint of engagement, hook end 48 of shutter lever 48 mates with catch516. After the shutter lever 48 has engaged shutter catch 516, the forceof insertion (supplied by the user) of cartridge 10 further into drive50 will cause shutter 16 to rotate in tandem with lever 48 in thecounter-clockwise direction. The rotation of lever 48 against theclockwise spring bias loads the spring of lever 48. Similarly, therotation of shutter 16 against the bias of spring 21 loads shutterspring 21. Accordingly, when cartridge 10 ejects from drive 50, spring21 causes shutter 16 to snap shut and lever 48 to return to a positionproximate the position shown in FIG. 11B. FIG. 11D shows the firststages of shutter 16 rotation as cartridge 10 moves further into drive50. FIG. 11E shows the complete insertion of cartridge 10.

Shutter 16 and lever 48 disengage in essentially the reverse sequencefrom that described above in connection with FIGS. 11A-11E. However, theejection of cartridge 10 from drive 11 is aided by spring 21 ofcartridge 10. In particular, as cartridge 10 ejects from drive 50, theforce of spring 21 rotates shutter 16 in the clockwise direction. Theforce of spring 21 causes catch 516 to impinge upon upstanding tab 148.This force also causes cartridge 10 to move outwardly from drive 10. Ofcourse, this force to move the cartridge outwardly diminishes as theshutter lever moves clockwise toward its pre-loaded position. Furtherdetails of a disk drive insertion and ejection mechanism are describedin co-pending patent application Ser. No. 08/968,561 entitled "METHODAND APPARATUS FOR CARTRIDGE EJECTION AND OVERWRITE PROTECTION " filedNov. 12, 1997, which is hereby incorporated by reference in itsentirety.

FIG. 12 shows an isometric view of the underside of cartridge 10. Hub 12is disposed in spindle access hole 218b of cartridge 10. Hub 12comprises a substantially flat bottom surface 12e, and an inner ring12c, and an outer peripheral edge 12b. Also shown in FIG. 12, bottomshell half 18b has a rounded edge 218c around drive access hole 218b.Hub 12 and rounded edge 218c interact to restrain lateral movement ofdisk 14 within cartridge shell 18.

Unconstrained lateral movement of disk 14 within cartridge 10 couldcause the edges of disk 14 to impinge upon the inner circumference ofshutter 16. Such impingement could damage disk 14 causing data loss orworse. Referring also to FIG. 13 (a cross section of FIG. 12 along theline 13--13), hub 12 and attached disk 14 are free to move laterally (inthe x and y plane) within cartridge 10 by the distance indicated by line112. However, hub 12 projects outwardly from drive access hole 218b (seealso FIG. 6). This projection of hub 12 is much more pronounced thanwith conventional floppy disk cartridges. The projection is sopronounced that even if hub 12 is pushed up (in the z direction) intocartridge 10, hub 12 still projects out from drive access hole 21 8b.The overall effect of the hub projection is to prevent disk 14 frommoving laterally so that its edges contact the inner circumference ofshutter 16.

During insertion of cartridge 10 into drive 50, spindle 40 remains fixedand cartridge 10 slides in a fixed plane relative to spindle 40. Inother words, unlike typical cartridge insertion mechanisms used in otherdisk drive systems, in present drive 50 and cartridge 10 there is notranslation of either cartridge 10 or 40 in the z-axis. Accordingly, tomount hub 12 to spindle 40, hub 12 undergoes z-axis translation as itslides along the top surface of spindle motor 53 and over spindle 40.This z-axis translation of hub 12 is best illustrated with reference toFIGS. 14A-14C, which present cut-away side views of cartridge 10 anddrive 50 that loosely correspond in relative position to cartridge 10and drive 50 in FIGS. 11, along lines 14--14.

Peripheral edge 12b preferably forms angled outer surface that isadapted to engage with a rounded edge of the spindle access openingduring upward translation into shell 18. The preferred angle a for theouter edge is about 45 degrees. More preferably peripheral outer edge12b substantially forms a ring around the circumference of hub 12.However, other configurations could accomplish a similar function, suchas spoke-like or fingers of angled surfaces rather than a solid annularsurface depicted in the figure. Similarly, inner ring surface 12c,preferably substantially ring shaped, could also comprises a differentform, for example a series of fingers. Inner ring surface 12c also has apreferred angle, β, of about 45 degrees.

As shown by the cut-away side views, hub 12 has a stepped side profile.Disk 14 is attached to the hub along a topmost surface 12h of hub 12. Astep down from top surface 12h is a surface 12j , which forms the top ofperipheral outer edge 12b. The step provides a gap 13 between the hub 12and disk 14. As is described more fully below, gap 13 providesadditional flexibility for vertical translation of hub 12 withincartridge 10.

Spindle motor 40 has several features that are adapted to interact withhub 12. In particular, spindle 40 includes the "z" datum 40a (providedby a raised ring), a round boss surface 40b and a conical lead-in groove40c. All of these features cooperate to enable engagement anddisengagement of hub 12 from spindle 40. In addition, the top of spindle40 is magnetically sensitized to attract and magnetically couple hub 12to spindle 40.

Significantly, hub 12 engagement and disengagement from spindle 40occurs without translating the plane of cartridge 10 vertically (i.e. inthe z-axis direction) relative to the plane of the drive or withouttranslating the spindle motor. Consequently, the height of drive 10 canbe thinner than is possible in either a spindle or cartridge translationmethod. Instead of translating either the spindle or the cartridge, hub12 and media 14 are translated along the z-axis within shell 18 as thecartridge is translated linearly (i.e., along a plane substantiallyparallel to the x-axis) into and out of drive 50. No additional space isrequired within cartridge shell 18 to accommodate the z-axis translationof hub 12, other than space which is already available to allow disk 14to spin freely within shell 18. The present invention can even functionproperly with less interior cartridge space than that provided in acommon 3.5 inch disk cartridge.

During insertion of cartridge 10 into drive 50, as depicted in FIG. 4A,hub 12 slides on inner ring surface 12c over the relatively planarprofile of the bottom of chassis 57 and over the top of spindle 40. Thering surface provided by inner ring 12c provides a relatively largesurface area for hub 12 to slide upon during insertion into drive 50.This large surface area ensures that the hub slides smoothly into drive50. Downwardly projecting pin 20 is coupled proximate the center ofcartridge 10 to top shell portion 18a. The downwardly projecting pin 20,engages sidewall 12a of hub 20 urging it into chassis 57.

A force applied to cartridge 10 during insertion causes pin 20 to pushagainst the sidewall of bore 12a. This pushing provides a force toovercome the friction between inner ring surface 12c and chassis 57 andtop of spindle 40. As cartridge 10 reaches far enough into drive 50,inner ring surface 12c aligns with conical lead-in groove 40c. At thatpoint, the magnetic force provided by spindle 40 attracts and pulls hub12 into engagement with spindle 40, resulting in inner ring surface 12cextending into conical lead-in groove 40c. As best shown in FIG. 4B, theangles of lead-in groove 40c and inner ring surface 12c, preferablyproximately 45 degrees, are such that hub 12 properly aligns on centerwith spindle 40 as hub 12 is pulled into a seated position. Inparticular, inner ring 12c forms a cone-like male surface thatcorresponds with the cone-like female opening of lead-in groove 40c. Asthe two cone-like surfaces engage, inner ring 12c is guided by conicallead-in groove 40c. Moreover, the relatively large diameter of innerring surface 12c (as measured across hub 12) and conical lead-in groove40c ensures a highly accurate alignment of hub 12 to spindle 40.

As cartridge 10 ejects from drive 50, hub 12 disengages from spindle 40,again, without vertical translation of cartridge 10 with respect todrive 50 (only hub 12 and media 14 translate in the z-axis). As bestshown in FIG. 4C, when cartridge 10 starts ejection from drive 50,cartridge shell 18 moves outwardly from drive 50. During this outwardmovement of cartridge shell 18, hub 12 initially remains seated onspindle 40. A force is required to cause disengagement of hub 12. Therequired force is provided by the movement of cartridge shell 18relative to hub 12. Cartridge shell 18 has downwardly projecting pin 20and rounded edge 18c that cooperate with hub 12 to facilitatedisengagement.

Disengagement begins when pin 20 impinges on the sidewall of bore 12a.Substantially simultaneously, rounded edge portion 18c contacts theangled peripheral outer edge 12b. As shell 18 continues to moveoutwardly, rounded edge 18c slides against angled peripheral edge 12b.The horizontal movement (along the x-axis) of rounded edge 18c relativeto angled edge peripheral edge 12b urges a lifting hub 12. The combinedimpingement of pin 20 and lifting of shell 18b cause hub 12 to tiltabout datum 40a. As hub 12 tilts, inner ring surface 12c also tilts.When the bottom surface 12f of inner ring 12c clears the top 40d ofspindle 40 hub 12 can also move begin moving outwardly with cartridge10. As hub 12 moves outwardly, angled inner ring surface 12g engagesangled spindle lead-in groove surface 40c. Because both surface areangled, hub 12 slides up the side of lead-in groove surface 40c.

As best shown in FIG. 14D, when bottom surface 12f of inner ring 12cclear datum 40a of spindle 40, hub 12 is free to move with cartridge 10.Thereafter, pin 20 urges hub 12 to travel in tandem with cartridge shell18. The force of pin 20 continues to drag hub 12 over the surface ofspindle motor 53 and chassis 57 until cartridge 10 has ejected fromdrive 50.

The stepped profile of hub 12 allows for additional headroom as hub 12tilts within cartridge 10. That is, without a stepped hub, the tiltingcould cause the top of hub 12 to impinge upon the inner top surface ofshell 18a and interfere with the disengagement of hub 12 from spindle40. Moreover, the stepped hub allows the disk 14 to flex as hub 12 istilted during disengagement.

A best illustrated in 14A, hub 12 is translated in the z-axis directionduring cartridge 10 insertion into drive 50. As a result, disk 14 ispush upward to the inner surface of upper shutter shell 16a an againstliner 15a (not shown in this Figure for clarity). This upwardtranslation of hub 12 allows it to clear the top of spindle 40.

However, as a side effect of the upward location of disk 14, the edge ofdisk 14 must be adjusted downwardly to thread the head loading ramps 47as described more fully below.

FIG. 15A shows an isometric view of the load ramp in accordance with thepresent invention. Load ramp 47 comprises a base 67, head guard 61,pivoting arms 60a and 60b, abutments 66a and 66b, pivot pin 65, andcompression spring 69. Each arm 60a, 60b comprises a ramped end portion64a, 60b and a tail portion 63a, 63b. Pivoting arms 60a and 60b arearranged to pivot about pivot pin 65 in opposing fashion between an openposition, in which the ramped ends pivot away from each other, and aclosed position in which the ramped ends pivot toward each other. Spring69 is disposed between the arms 60a and 60b such that the arms 60a and60b are biased toward the closed position. Tail portions 63a and 63b ofarms 60a and 60b, respectively, engage the corresponding abutments 66aand 66b to restrain the rotational travel of arms 60a and 60b when theyare biased toward the closed position. Base 67 also comprises a hole 70for attachment to the drive chassis 57 by means of a screw or othercommon attachment means. Head guard 61 extends out from the base 67 andprovides opposing surfaces 61a and 61b. Each surface 61a and 61b has aramped front portion 62a and 62b, respectively. Each of these surfaces61a and 61b provides a surface for heads 54 to rest when the actuator 56is in the parked position.

Referring now to FIG. 15B and 15C, side views of load ramp 47 are shown.In FIG. 15B, pivot arms 60a and 60b are in the open position, withspring 69 compressed (by load beams 44, which are not shown forclarity). Accordingly, the distance between ramped end portions 64a and64b is maximized. With the distance thus maximized, media 14 enteringbetween the end portions 64a and 64b has sufficient space to fluctuateduring loading without a collision between media 14 and load ramp 47. InFIG. 15C, the pivot arms 60a and 60b are in the closed position. Oncethe media is fully inserted into drive 50, pivoting arms 60a and 60b cansafely close over media 14 without damage to media 14. With arms 60a and60b in the closed position, heads 54 can safely move between media 14and load ramps 47.

Because hub 12 and disk 14 are translated upwardly from hub 12 slidingover chassis 57, when hub 12 is compressed into liner 15a, disk 14 isforced out of plane. Forcing disk 14 out of plane in this way causes alarge distortion at outer peripheral edges of disk 14. The edgedistortion, in turn, could cause disk 14 to travel over the top of loadramp end portions 64a, 64b rather than properly threading between endportions 64a, 64b. An adjustment to the disk 14 at the disk accessopening is necessary to ensure that disk 14 properly threads betweenload ramps end portions 64a and 64b.

Accordingly, referring now to FIG. 16, an isometric bottom view of uppershutter shell half 16a with attached liner 15a is shown. Liner 15a isattached to the inner surface 216a of shutter half 16a. Liner 15a is cutaround post hole 316a exposing a portion of inner surface 16a (about thesize of drive access hole 316b ). Distortion neutralizer 11 is disposedon surface 216a of shutter half 216a proximate the apex of wedge-shapeddisk access opening 416a. (See also FIG. 7). Media distortionneutralizer 11 comprises a raised surface on inner surface 216a. Theraised surface can be formed by attaching material to surface 216a. Thethickness of the distortion neutralizer is at least one thickness ofliner 15a and no thicker than about half the thickness of the spacebetween shutter shell halves 16. Most preferably, it is about 0.2 mmthick. The width of distortion neutralizer 11 is limited by therelatively small size of the present cartridge 10. That said, it isfurther limited by the distance between the edge of disk access opening416a and hub 12. Accordingly, the width is between about 1 and 2 mm,preferably about 1.5 mm. Preferably, the raised surface is formed bystamping the distortion neutralizer directly into upper shell half 16a.Moreover, shell liner 15a is preferably attached over the top of theraised surface to protect disk 14 from direct metal contact on mediadistortion neutralizer 11. Media distortion neutralizer 11 is preferablyarced, more preferably the arc is a portion of a circle so as to beconcentric with disk 14; however, it could also be substantiallystraight. Thus, when cartridge 10 is assembled, media distortionneutralizer provides a ridge of material projecting downwardly from anupper surface of cartridge 10. This projecting surface ensures that disk14 is forced downwardly toward the a plane proximately more centeredbetween upper and lower cartridge halves 18a, 18b. The more centereddisk 14, therefore, more reliably threads between head load ramp ends64a, 64b during cartridge insertion into drive 50.

The above description of preferred embodiments is not intended toimpliedly limit the scope of protection of the following claims. Thus,for example, except where they are expressly so limited, the followingclaims are n-t limited to applications involving cartridges for diskdrive systems.

What is claimed is:
 1. A cartridge for use in a removable media diskdrive having a spindle for coupling with said cartridge, said cartridgecomprising:an outer shell having a first spindle access opening and afirst head access opening, said first head access opening being disposedin a front portion of said outer shell and contiguously along top,front, and bottom sides of the outer shell; an inner shell having asecond spindle access opening and a second head access opening, saidsecond head access opening disposed in a front portion of said innershell and contiguously along top, front, and bottom sides of the innershell, said inner shell being rotatably coupled to said outer shellbetween first and second positions, and wherein said spindle accessopenings are substantially aligned, said inner shell being selectivelyrotatable to said first position such that said head access openingssubstantially align and said second position such that said head accessopenings are substantially misaligned; a substantially circular magneticmedium rotatably disposed within said inner shell such that said innershell encloses at least half of said magnetic medium.
 2. The cartridgeas recited in claim 1 wherein said inner shell comprises upper and lowerinner shell halves having raised outer edges, wherein said edges overlapin frictional engagement to form a single inner shell.
 3. The cartridgeas recited in claim 1 wherein said inner shell is substantiallydisc-shaped and has a hollow interior wherein said magnetic medium isrotatably disposed.
 4. The cartridge of claim 1 wherein said inner shellcomprises a sheet metal.
 5. The cartridge as recited in claim 4 whereinsaid sheet metal is aluminum.
 6. The cartridge as recited in claim 1wherein said head access openings in at least one of said outer shelland said inner shell are substantially wedge-shaped.